In the field of paper crafting, pieces of paper or cardboard of various shapes are punched out from sheets of paper or cardboard by paper punches. A conventional paper punch is shown in FIGS. 1 and 1A and generally designated as 10. The paper punch 10 has a lever 12 operatively associated with a main body 14. A generally horizontal slot 16 is provided in the main body 14 for insertion of a sheet of paper or cardboard 18. The lever 12 may then be pivoted downwardly to move a die (not shown in FIG. 1, 1A or 2) to punch or cut out a piece of shaped paper or cardboard 18a from the piece of paper or cardboard 18, as shown in FIG. 2.
As shown in FIG. 3, the punch 10 has a die 20 with an upper flat plate 26 which is operatively associated with the lever 12. The die 20 is integrally formed with an endless, downwardly-depending wall 28. On an underside of the wall 28 is formed an undulating cutting edge 30. The punch 10 also has a die holder 24 with an upper jaw 31 and a lower jaw 32 which are joined at a rear end 34 thereof. A piece of paper or cardboard may therefore be inserted through a slot 35 between the upper and lower jaws 31, 32 of the die holder 24. Each of the upper and lower jaws 31, 32 is formed with a hole which are aligned with each other and are so shaped and sized to just allow the wall 28 of the die 20 to pass through. Thus, when a piece of paper or cardboard is received within the slot 16 of the punch 10, and thus within the slot 35 of the die holder 24, upon downward movement of the lever 12, the cutting edge 30 of the die 20 will shear the piece of paper or cardboard to punch or cut out a piece of shaped paper or cardboard.
In conventional paper punches, both the die and the die holder are made of metal or metal alloy (such as copper, aluminium, silver, zinc or tin) by low pressure die cast, e.g. by injection moulding. Although the cost of the paper punches may be reduced if at least part of the die or die holder is made of a plastics material, it has long been held by people in the field that such would jeopardize the proper alignment between the die and the die holder, in particular during the course of relative movement between the die and the die holder in the punching action. It is also believed that the strength and rigidity of the die may be compromised if part of it is made of a plastics material. In particular, as the die is made integrally of a metal or metal alloy, if, after prolonged use, part of the die (e.g. the cutting edge) is damaged, the whole die has to be disposed of or re-cast, which is not economical.
It is thus an object of the present invention to provide a paper punch die and a paper punch in which at least one of the aforesaid shortcomings is mitigated, or at least to provide a useful alternative to the trade and public.